The present invention relates to a circuit system for configuring an interface of a control or regulating device, especially an electronic controller of a vehicle control system, such as ABS, EBD, TCS, or ESP, to a signal transmission system, especially a serial vehicle bus system, such as a CAN bus, by an interface module. Further, the present invention relates to a method of configuring an interface of a control or regulating device, especially an electronic controller of a vehicle control system, such as ABS, EBD, TCS, or ESP, to a signal transmission system, especially a serial vehicle bus system, such as a CAN bus, wherein the interface is provided and adaptable by means of an interface module for the signal transmission system.
Functionality, operating facility, comfort, and safety have been improved greatly in the past years by the technical development of vehicles, in particular automotive vehicles, among others by the use of electronic control or regulating systems, such as driving safety systems (anti-lock system (ABS), traction slip control system (TCS), or Electronic Brake Force Distribution (EBD)), driving dynamics control (ESP), electronic engine control and driver information and communications system. This involves a considerable increase in the exchange of data between the electronic components, with the result that the number and length of electric lines of the network system and the number of electric plug connections is constantly increasing. Conventional cabling techniques can scarcely cope with the demanded data exchange between the individual control devices and various terminal devices, such as operating elements, sensors and consumers/actors (e.g. motors, valves or indicating elements).
These problems can be solved by the use of serial bus systems. Special bus systems, especially the so-called xe2x80x98CAN busxe2x80x99 (Controller Area Network, described in ISO 11 519-2 and ISO 11 898), the so-called xe2x80x98SCP busxe2x80x99, the so-called xe2x80x98VAN busxe2x80x99 or the so-called xe2x80x98J1850 busxe2x80x99 ha[b]ve been developed for application in automotive vehicles. The control or regulating devices, that means in particular the microcomputers, in the bus system communicate by way of interfaces and the bus with the other system components. To this end, corresponding signal lines and electronic/electric components such as signal conditioners, transmitters, receivers, and control devices are provided which sense or output individual signals or reports (messages which contain several signals) or directly switch on or off the electric consumers/actors.
The CAN bus gained acceptance as a standard especially for the application in automotive vehicles. A number of equally entitled control or regulating devices are interconnected in the CAN bus by a linear bus structure. Coupling of the individual customers to the bus structure is effected by a bus node. A bus node is basically composed of the control or regulating devices and an interface module (interface controller).
The data for an individual message and signal processing operation and the initialization parameters for the interface configuration is/are invariably implemented in the control or regulating program of the control or regulating device (microcomputer).
On the basis of the stored data for the individual message and signal processing operation or of initialization parameters for the interface, the type of operation of the bus (type of operation of the output drivers and condition of the interface) are initially adjusted by the microprocessor by means of the interface module.
A change of the implemented interface configuration is possible only with a relatively high expenditure, that means, repeated programming of the microcomputer with a subsequent compiling and linking of the current program [2] is necessary.
An object of the present invention is to improve the prior art circuit system and the prior art method of configuring an interface of a control or regulating device, especially an electronic controller of a vehicle control system, to a signal transmission system, especially a vehicle bus system, such as a CAN bus, and to permit a flexible and safe new configuration which is technically simple to achieve.
A principal aspect of the present invention involves that the circuit system includes a first memory which depends on the control or regulating device and has a first signal table which contains data for describing substantially all possible signals which are provided to the signal transmission system by way of the interface, and that the circuit system includes a second memory which is independent of the control or regulating device and has a second signal table which contains the current data for describing the current interface.
Thus, according to the present invention, the signal tables are split in two segments or, respectively, two signal tables are provided: a first (internal) signal table and a second (external) signal table. These separate table segments or tables are associated with two separate memories or memory areas. The advantage of the present invention lies basically in that the second memory or the data stored therein, in contrast to the first memory, is not directly involved in the current program of the control or regulating device and, thus, is principally relatively easy to modify or adapt.
The term xe2x80x98two separate memoriesxe2x80x99 in the sense of the present invention means that two separate memory modules are provided and, also, that a separation can be achieved by two separate memory areas in one single memory module;
This is advantageous in that updating of the data in the second signal table and, thus, establishing or adapting an interface to a predetermined signal transmission system, in particular a vehicle bus system, can be achieved flexibly, quickly and in a technically simple fashion. For example, it is arranged for to employ easy-to-modify memories, such as RAM memories (especially buffered RAM memories), flash memories or EEPROM memories as modules for the second memory.
When the data prevails in a modifiable memory, an xe2x80x98offlinexe2x80x99 or xe2x80x98onlinexe2x80x99 modification of the data is possible.
In the modification referred to herein by the term xe2x80x98offlinexe2x80x99, the signal table is modified by means of a memory configuration device, preferably by an external program. The result comprises data or a table in a language which is compatible to the programming language used for the current program of the control or regulating device. This data or table is subsequently integrated into the current program by compiling and linking. Thereafter, the entire program must be loaded, e.g. by download, into the control or regulating device or [said""s] corresponding component, especially microprocessor.
For a modification referred to as xe2x80x98onlinexe2x80x99, the signal table is also modified according to the present invention by a memory configuration device, preferably, by an external program. In this case, however, the result comprises data or tables in a form, e.g. a binary code, which can be downloaded directly into the memory of the control or regulating device or the microprocessor. A modification of the second signal table in the second memory by means of online modification is preferred in the present invention.
It is also envisaged in the present invention that several different variations of the signal tables are stored in a non-modifiable memory, e.g. a ROM, and a defined variation is selected in a case of need. Preferably, this selection can also be performed online for the second signal table.
The first signal table is preferably produced when the function code for the control or regulating device is developed, that means in the compiling and linking operation (offline modification). All signals described in this first signal table can (but do not have to) be supplied to the signal transmission system. The first signal table can easily be modified by a memory configuration device, preferably by an external program, e.g., by inserting or removing new signals. The modifications are only adopted into the current program [2] of the control or regulating device or the microcomputer in the new translating and linking operation.
According to the present invention, the first signal table includes for each signal at least data for the signal type (e.g. a timer for the signals set, reset or timer, an up to 16 bit long character string for a signal, a 1 to 64 bit long character string for a block and/or a constant), for the position (e.g. a RAM address), for the length of the signal, and for the signal origin (e.g. a RAM address) and a special name for describing the function of the signal.
The second signal table contains the current interface description and is easy to modify retroactively by a configuration device, preferably by an external program. The second signal table contains at least data for the initialization of the interface (e.g. a Baud rate for the transmission speed and a bit timing for the interface configuration), for the type of messages transmitted (e.g. a time-controlled and/or event-driven report-related rate of repetition as a transmitting or receiving pattern) and for a type of report (e.g. transmitting or receiving report) as well as for the number of signals contained in the message (e.g. for the position and length of the signal within the message), and for the allocation to the data in the first signal table.